1. Field
One or more embodiments relate to a bi-functional compound, positively charged at a first pH and negatively charged at a second pH, a solid support comprising the bi-functional compound, and a method of isolating a nucleic acid using the same.
2. Description of the Related Art
Methods of isolating a nucleic acid by using a pH-dependent ion exchange material typically include, for example isolating a nucleic acid by treating a solution of the nucleic acid with a material having an ionizable group, such as an acidic functional group or basic functional group, which is positively charged at a first pH, thereby binding the nucleic acid, and subsequently releasing the nucleic acid at a second pH that is higher than the first pH. Examples of materials having such an ionizable group include N-2-acetamido-2-aminoethanesulfonic acid (“ACES”), N-2-acetamido-2-imidodiacetic acid (“ADA”), N-trihydroxymethyl-methyl-2-aminoethanesulfonic acid (“TES”) and tris(hydroxymethyl)aminoethane (“Tris”), each of which is a common, commercially available buffer compound. In other methods of isolating a nucleic acid, a pH dependent ion exchange material may be used which includes a support such as a silica-coated magnetic particle with a plurality of first ion exchange ligands, in which each first ion exchange ligand includes an aromatic hydrocarbon ring, a spacer which covalently attaches the ion exchange ligand to the aromatic hydrocarbon ring, and a linker which includes an alkylene chain and which is attached to the silica magnetic particle at one end and to the spacer at the opposite end.
However, despite these methods, there is remains a need for materials which bind efficiently to a nucleic acid, and which also efficiently release the nucleic acid in the reaction of isolating the nucleic acid.